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Need some help. Battering ram.

11-08-2008, 08:52 AM

As some of you know I have been actively involved with a project r&d team. It's a couple friends of mine and the project has gone very well. We're just trying to solve a small issue. On the one end of a 4" box tube there is an open end that needs to be capped. For cost reasons a molded plastic press in type cap was originally used and then there were some issues during testing of it popping out. Now a special epoxy has been used and the epoxy never breaks but the kinetic energy is actually causing the caps to break along the molding/casting reinforcements. They like the idea of welding a diamond plate cap over the end and it looks awesome but in all reality a full corner weld and precies fitment is need to make it look right and that's not very cost efficient. Just wondering if anyone else has any other ideas for a cap that would stay in place. This is an impact device and creates alot of kinetic energy that does some unimagineable things. Anyways.....that's where I'm at for now. Thanks again all. Dave

Comment

Shear or have sheared end caps that are the same size as the id of the tube. Then set them on the ends, tack them, then weld around it. The square corners of the plates will sit on the round corners of the tube so as not to "fall in" when fitting. Use a mig to weld them. It won't take more than a couple minutes a piece shearing included. Once you get set up there will be no clean up as the corner to corner joint will leave you with a nice rounded corner with no grinding.

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How important is the looks? If its a battering ram, won't the end get beat up from use. Does the end have to be flat?

What I was thinking is you could cut the corners of the tube down, bend the flaps in and weld them. Depending on how far down you cut the corner, and what shape you make the cuts, you could go from a 4 sided point to a round end. Once the shape is determined you can program the cut into a CNC or make a pattern to make the cuts by hand.
Depending on the tube thickness, you can tap the flaps over with a mallet until the edges meet or make a pattern to slide into the tube to pound the flaps down on.
If it does not have to be a show room quality the edges will come well within reason for welding. I have seen guard posts done like this. Now if the end has to be flat, this method would be much more difficult.

Comment

Shear or have sheared end caps that are the same size as the id of the tube. Then set them on the ends, tack them, then weld around it. The square corners of the plates will sit on the round corners of the tube so as not to "fall in" when fitting. Use a mig to weld them. It won't take more than a couple minutes a piece shearing included. Once you get set up there will be no clean up as the corner to corner joint will leave you with a nice rounded corner with no grinding.

This is how I did the last two non plastic caps. They look awesome. Made the caps from diamond plate and they like the looks but it's too time consuming. That's alot of weld wire and weld time when mass producing. Looking maybe at a premade cap that holds better under alot of force. Don't get me wrtong, the diamond plate caps turned out killer, but the idea is to save money while being functional. Dave

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It's not about pinching a penny but when you are in the business to be making money, a small amount of time saved in the long run can equal a great amount of money. The reason I am asking in the first place is because the original caps were too cheap for the purpose. I am not trying to design a cheap pos but rather keep things simple to keep costs down. Simple does not mean poor quality. Dave

Comment

You have a point but,,, if this is a deal breaker then this product is likely under priced to start with. Even effort to source different materials and change a process when you have the equipment at hand may not be worth the effort. In this kind of product the money is made on the marketing end, not primarily on the production and it relies heavily on its quality and low warranty claims, it cant afford a customer to perceive it as a pos, real or not. I would be very leery of putting a piece of plastic on this fine tool, it really sabotages the marketing efforts.

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Look at the controversy changing a wire feed drive roller holder or whatever it is from cast alum to plastic causes, its inside the machine cover and dont mean squat but once a customer owns that in his mind its about impossible to change.